Optical Disc Device

Abstract

There has been an issue that the operation of a semiconductor circuit performing edge timing control cannot follow up in the multipulse generation process where high multiplication of speed progresses every year. A light strategy drive comprises a control register ( 22 ) storing timing edge information for generating the edge of a recording waveform signal, a PLL ( 23 ) generating a clock for generating the edge of a recording waveform signal, and a timing control circuit ( 24 ) for receiving timing edge information corresponding to the recording waveform signal from the control register ( 22 ) to output timing edge information having a predetermined amount of delay in parallel and compounding the edges based on the timing edge information outputted in parallel. Timing edge can be controlled with high precision even at the time of high speed operation, and a high precision multipulse can be generated.

1 . (canceled) 
     
     
         2 . An optical disc device including a laser power control unit which controls power of laser for recording a digital signal sequence on a recording medium, a write strategy unit which divides the recording power and generates a multipulse for accurate pit formation, and a laser diode driver which emits laser according to the multipulse from the write strategy unit, said optical disc device generating a recording waveform signal having edges and amplitudes corresponding to the digital signal sequence, wherein
 said write strategy unit comprises:   a storage unit for storing timing edge informations to be used for generation of edges of the recording waveform signal;   a clock generation circuit for generating a clock for generating edges of the recording waveform signal; and   a timing control circuit for receiving the timing edge informations corresponding to the recording waveform signal from the storage unit, processing the inputted timing edge informations in parallel, generating edges on the basis of the parallel-processed timing edge informations, and synthesizing the generated edges; and   said timing control circuit comprises:   a space/mark length counter unit for receiving the digital signal sequence, and counting a space length and a mark length of the digital signal sequence;   a timing sequencer unit for making the storage unit successively output desired timing edge informations on the basis of a count value that is counted by the space/mark length counter unit;   a timer unit for controlling a delay amount of the clock on the basis of the timing edge informations outputted from the storage unit, and outputting time edge informations having a predetermined delay amount;   a parallel processing sequencer for controlling the outputting of the timing edge informations from the timer unit so that the timing edge informations are outputted in parallel; and   a parallel processing circuit for generating edges in parallel on the basis of the parallel-outputted timing edge informations under control of the parallel processing sequencer, and synthesizing the generated edges.   
     
     
         3 . An optical disc device as defined in  claim 2  wherein
 said storage unit includes one or plural tables each having a plurality of the timing edge informations;   said timing edge informations include address informations corresponding to the count values counted by the space/mark length counter unit; and   each table includes table address information corresponding to the table.   
     
     
         4 . An optical disc device as defined in  claim 3  wherein said timing sequencer unit controls outputting of the timing edge informations on the basis of the count values outputted from the space/mark length counter unit, with reference to the table in which the timing edge informations corresponding to the count values are stored. 
     
     
         5 . An optical disc device as defined in  claim 2  wherein, when the count value exceeds a predetermined value, said space/mark length counter unit performs a clipping process and outputs a maximum value that has previously been set. 
     
     
         6 . An optical disc device as defined in  claim 2  wherein
 the timing edge informations stored in the storage unit include at least plural fixed current values; and   the recording waveform generated in the parallel processing circuit is a recording waveform a current value of which is selected from among the plural fixed current values stored in the storage unit, according to the mark length and the space length in the section of the mark length.   
     
     
         7 . An optical disc device as defined in  claim 2  wherein the recording waveform to be generated in the parallel processing circuit has a period for outputting a constant current value to the laser diode driver, between a mark length and a mark length. 
     
     
         8 . An optical disc device as defined in  claim 2  wherein the timing edge informations inputted to the timer unit include at least delay amounts and current amounts. 
     
     
         9 . An optical disc device as defined in  claim 8  wherein
 said timer unit comprises:   a plurality of first selectors for parallel outputting the outputs of the timing edge informations having predetermined delay amount values, under selective control of the parallel processing sequencer, and   a plurality of second selectors for parallel outputting the outputs of the timing edge informations having predetermined current values, under selective control of the parallel processing sequencer;   said parallel processing circuit comprises:   an RS latch circuit which receives the timing edge informations outputted from the respective first selectors, as a data set signal and a reset signal, and   a current value output control circuit which receives the timing edge informations outputted from the respective second selectors, and outputs a synthesis edge having a predetermined current value on the basis of the data set signal, the reset signal, and the output from the RS latch circuit;   said data set signal and said reset signal are also input to the parallel processing sequencer; and   said parallel processing sequencer controls the timing edge informations so as to be outputted in parallel, according to the inputs of the data set signal and the reset signal.   
     
     
         10 . An optical disc device as defined in  claim 2  wherein said timer unit is constituted by one timer. 
     
     
         11 . An optical disc device as defined in  claim 2  wherein said timer unit is constituted by plural timers. 
     
     
         12 . An optical disc device as defined in  claim 2  wherein said parallel processing sequencer controls the timing edge informations that are successively outputted from the timer unit so that odd and even outputs thereof are outputted in parallel in the order of the respective outputs. 
     
     
         13 . An optical disc device as defined in  claim 2  wherein said parallel processing sequencer is connected to the space/mark length counter unit, performs a counter operation on the basis of an offset of a constant value, and performs sequencer control. 
     
     
         14 . (canceled) 
     
     
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         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . An optical disc device as defined in  claim 9  wherein said timer unit is constituted by one timer. 
     
     
         24 . An optical disc device as defined in  claim 9  wherein said timer unit is consituted by plural timers. 
     
     
         25 . An optical disc device as defined in  claim 9  wherein said parallel processing sequencer controls the timing edge informations that are successively outputted from the timer unit so that odd and even outputs thereof are outputted in parallel in the order of the respective outputs.